In the Linga Purana, there is mention of an astra called Mahesvara. Mahesvara is the name of Lord Shiva from Hindu mythology and in this context also refers to the astra of Lord Shiva.

Paraphrased: "Vishnu, the cool, collected, benevolent God of great Grace, started showing traces of annoyance towards Brahma and uttered a few Mantras and shot the Mahesvara weapon. Brahma was so agitated knowing the launch of such a weapon that he sent an antimissile missile called Pasupata weapon. The missiles met in the air and destroyed each other."

Pasupata is also the weapon of Lord Shiva, so it is unclear why Brahma and Vishnu are both using the astra of another deity, and why essentially the same astra is given two different names. The Puranas may be of less scholarly value than older texts such as the Mahabharata because there is an element of propaganda involved in which the writers were attempting to replace the Vedic / Upanishadic belief system which is based on intellectual thought with deity worship which is based on devotion. If you can shed some light on this topic please leave a comment.